The present invention generally relates to computer input devices. In particular, the invention relates to computer mice having input apparatus, such as a scroll wheel or a track ball, for scrolling a computer display.
It is commonly known to computer users that Windows based operating systems, such as Windows by Microsoft Corporation, and the applications that run under them, may only display a portion of a document or computer program on a display screen if the viewable area of the document or program is larger than the viewing area of the display screen. In this situation, a user must scroll through the document or program to view the entire document or program. Depending on the size and orientation of the viewable area of a document or computer program, the user may need to scroll in a vertical and/or horizontal direction. While scrolling may be accomplished by using software scroll bars generated by the windows based application, computer mice having scroll wheels or track balls may also be used to input scrolling commands.
Computer mice having scroll wheels are well known in the art. Scroll wheels are generally finger operated rotatable discs that protrude from a surface of the computer mouse. Typically, the scroll wheel is located between the two buttons of a conventional two button mouse and can be operated by the index finger. Although capable of performing many functions, scroll wheels are particularly useful for providing a user with a convenient and efficient way for inputting scrolling commands. Finger operated track balls have also been used to input scrolling commands and provide the added benefit of generating simultaneous vertical and horizontal scrolling inputs.
Prior art computer mice with scroll wheels or track balls allow a user to scroll a display at a rate relative to the rate of rotation of the scroll wheel or track ball. If a user rotates the scroll wheel quickly, the display screen also scrolls quickly. A variable and rapid scroll rate, however, can result in somewhat unpredictable movement of the viewed section of the document. Due to rapid movement of words and images on the display screen a user may become confused as to where he or she is in a particular document. This can result in inefficient computing.